// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}

int fun(int n)
{
	int ans=0;
	if(n==1)return 1;
	ans=fun(n-1)+n;
	return ans;
}

signed main()
{
	int ans=0;	
	//ans=fun(100);
	ans=(1+100)*100/2;
	ans=(1+99)*99/2;
	//...;
	ans=fun(100);
	ans=fun(99);
	cout<<ans;
	return 0;
}
